This week we are considering the visual system. Vision is a dominant sense in humans, and many animals rely heavily on the ability to process movement and visual detail for their very survival. But here is something you may not have considered: Have you ever noticed that animals like deer, raccoons, and dogs have "eyshine" at night? If you have ever taken a picture of your dog, you probably noticed that they don't have the typical "red eye." Rather, their eyes glow! How might this be explained? If you were looking at this visual feature from an evolutionary perspective, what adaptive advantage might it have? Are there possible disadvantages? Why don't humans have one? If you have a picture of your dog or your pet that you want to upload, this would be a great week to do that. For example, this is one of my dogs (Eggo!) with eye shine. A dog with eye shine (glowing eyes) standing in front of a Christmas tree